[maven-release-plugin] prepare release mapdb-2.0-beta2
[maven-release-plugin] prepare release mapdb-2.0-beta2

cocosli/mapdb,hangum/mapdb,jankotek/mapdb,jankotek/MapDB,codeaudit/mapdb,jankotek/MapDB,SleimanJneidi/mapdb,lamfire/mapdb,jankotek/mapdb,pettermahlen/mapdb,morfeo8marc/mapdb,sumit784/mapdb,ffjiao/mapdb,binarytemple/mapdb,ringoluo/mapdb